The present invention is concerned with .alpha.-ethynyl- and .alpha.-vinyl-3,4-disubstituted phenylalanines and especially the 3,4-dihydroxyphenylalanine species.
.alpha.-Methyl-3,4-dihydroxyphenylalanine, particularly its L-isomer, is a known antihypertensive agent. (U.S. Pat. Nos. 2,868,818; 3,344,023).
Novel .alpha.-ethynyl- and .alpha.-vinyl-3,4-disubstituted phenylalanines have been discovered. These novel alanines have pharmaceutical activity including antihypertensive action.